1. Field of the Invention
This invention relates to a method and apparatus for providing a cable assembly seal and strain relief and, in particular, where the apparatus comprises a pre-mold for use with an overmold to provide the seal and strain relief for electrical conductors terminated within an electrical housing.
2. Description of Related Art
Cable assemblies are commonly available having a connector housing containing a plurality of terminals, each of the terminals in a separate passage and connected to one of a plurality of similarly shaped and sized conductors. In such assemblies, it is desirable to seal the passages where the conductors enter the housing. It is also desirable to provide strain relief to reduce twisting or bending of the conductors with respect to the terminals and the housing.
U.S. Pat. No. 3,854,787 discloses the use of flexible flaps to provide strain relief. The flaps are either integral with the housing or connected with a sleeve portion that fits around the connector housing. The flaps are secured together, such as by nuts and bolts, capturing the conductors between the flaps.
U.S. Pat. No. 4,105,278 discloses the use of a mechanism for sealing the points where conductors enter a connector housing. A ribbon shaped cable containing a plurality of conductors having similar shapes and sizes enters the housing through a sealing mechanism. The housing is molded directly to the sealing mechanism under an elevated pressure, such as, by an injection molding process. The pressure from the injected material acts against lips of the sealing mechanism to urge the lips against the cable to impede wicking of the material along the cable beyond the seal.
Another way that seals and strain reliefs have been provided is through an elevated temperature, high pressure injection molding process without the use of lips as disclosed in U.S. Pat. No. 4,105,278. A mold or tooling is created for injection molding a material to encapsulate a specific set of uniformly shaped and sized conductors where they exit a housing. However, such tooling is expensive to make and economically unjustified for making small quantities of such connector assemblies. Further, a different mold is needed for differently shaped and sized conductors. Moreover, injected material does wick out of the mold between cables, especially when the cables vary in shape or size.
It is considered desirable to have a method and apparatus for providing a connector assembly seal and strain relief through an injection molding process that permits the repeated use of tooling for conductors of varying shapes and sizes and eliminates leaking or wicking out of the injected material.